It sounds like you're referring to a specific session from the Hackers League Bootcamp where Lev Chizhov gave a presentation on how to build a Telegram Mini App.

This particular session, titled "Hackers League Bootcamp | Lev Chizhov | How to build a Telegram Mini App," was streamed approximately 9 months ago (around October 2024, given the current date of July 2025). It appears to have been part of a broader series of bootcamps and hackathons organized by the TON Society (The Open Network), aimed at educating developers and fostering innovation within the TON ecosystem by leveraging Telegram Mini Apps.

Key takeaways and context for such a session would typically include:

Introduction to Telegram Mini Apps: What they are (web applications running inside the Telegram messenger using HTML, CSS, JavaScript), their benefits (no separate downloads, seamless user experience, direct access to Telegram's user base), and their potential for various use cases (games, utilities, e-commerce, Web3 integrations).

Technical Foundations:

Telegram WebApp API: How Mini Apps interact with the Telegram client (e.g., getting user data, controlling the main button, haptic feedback, managing the theme).

Frontend Technologies: Basics of building the web interface using standard web development frameworks (React, Vue, etc.) or vanilla JavaScript.

Backend Integration: How the Mini App can communicate with its own backend server for data processing, logic, and integration with other services.

Development Tools and Environment:

Setting up a development environment.

Using BotFather to configure and enable Mini Apps for your Telegram bot.

Debugging and testing Mini Apps.

Key Features and Capabilities Discussed by Lev Chizhov:

Seamless Authorization: How users are automatically logged in.

Telegram Payments (with Telegram Stars, Google Pay, Apple Pay): Monetization options within Mini Apps.

User Data Access: Safely accessing user information.

Push Notifications: Delivering tailored notifications.

Newer Features (as per TON's ongoing development): Recent updates often include enhanced storage options (DeviceStorage, SecureStorage), improved UI customization for loading screens, and deeper integration with TON blockchain features for Web3 use cases (e.g., wallet functionalities, token interactions).

Best Practices for Building Mini Apps:

Mobile-First Design: Ensuring responsiveness and optimal experience on small screens.

Performance: Keeping the app lightweight and fast-loading.

User Experience (UX): Following Telegram's design principles for a consistent and intuitive feel.

Monetization Strategies: How to integrate paid subscriptions or gifts using Telegram Stars.

Lev Chizhov, as a speaker at a Hackers League Bootcamp (which is deeply tied to the TON ecosystem), would likely emphasize the integration of Telegram Mini Apps with the TON blockchain, discussing how developers can leverage TON's speed, low fees, and growing user base for decentralized applications (dApps) within Telegram.

These bootcamps are generally designed to equip developers with practical skills to build and deploy projects rapidly, often with a focus on hackathon-style development and pitching.